Electronic and Lattice Dynamics in The Photoinduced Ionic-to-Neutral Phase Transition in a One-Dimensional Extended Peierls-Hubbard Model

摘要

Real-time dynamics of charge density and lattice displacements is studiedduring photoinduced ionic-to-neutral phase transitions by using aone-dimensional extended Peierls-Hubbard model with alternating potentials forthe one-dimensional mixed-stack charge-transfer complex, TTF-CA. Thetime-dependent Schr\"odinger equation and the classical equation of motion aresolved for the electronic and lattice parts, respectively. We show how neutraldomains grow in the ionic background. As the photoexcitation becomes intense,more neutral domains are created. Above threshold intensity, the neutral phaseis finally achieved. After the photoexcitation, ionic domains with wrongpolarization also appear. They quickly reduce the averaged staggered latticedisplacement, compared with the averaged ionicity. As the degree of initiallattice disorder increases, more solitons appear between these ionic domainswith different polarizations, which obstruct the growth of neutral domains andslow down the transition.